CALLY OF DUTY: Ryan Callahan, Rangers captain at just 24, skates during practice for the Winter Classic last month. Photo: Reuters

BOSTON — He is the officer as infantryman, the leader who volunteers for the grunt work.

He is Ryan Callahan, the right captain at the right time for the right team.

“He’s a second-, third-, fourth-effort guy who leads by example, you know what I mean?” Brad Richards asked rhetorically before the Rangers brought their seven-point conference lead over the Bruins here for tonight’s test in a series of them for Callahan and his band of brothers. “He’s not a rah-rah guy, he’s not 38 years old with 18 years of experience.

“But all our guys follow him, and we follow him because night in and night out, his level of effort is always going to be the highest of anybody on the ice for both sides.”

Callahan is 26, not 38, is in his fifth year in the NHL, not 18th, and is in his first year as captain after serving two years as an alternate to Chris Drury. And though he might have acted as de facto captain much of last season when injuries limited Drury to 24 games, never before had the “C” been stitched onto his Blue Shirt just up above where his heart beats.

“I would imagine it must have been overwhelming for him to be captain so early in his career, but you’d never know that with the way he’s responded to it,” said Henrik Lundqvist, a teammate since 2006-07. “He’s the same guy I’ve always known.

“To me, his leadership comes from the way he plays. The way he sacrifices, it makes it easy for guys to step up for him. If there’s a style, that’s what it is.”

Callahan is second on the Rangers with 22 goals and has eight in the last 11 games, but scoring does not define him. Despite twice being sidelined last year with broken bones (one hand, one ankle) he sustained while blocking shots, Callahan continues to throw himself on grenades.

The captain leads Rangers forwards in blocked shots and hits, and is fourth in the NHL in both.

“Cally is a watch-what-I-do leader more than a listen-to-what-I-say guy,” said Marc Staal, a teammate for four years. “With me coming back in the middle of the season, I can’t tell you that I see any difference in his personality.

“He’s the lead voice of our team and if there’s one guy who talks to Torts [coach John Tortorella] on the team’s behalf it’s him, so that’s a change, but it hasn’t changed him.”

Callahan told The Post that while the captaincy hasn’t altered his game or his relationship with his teammates, it has had an impact on his approach.

“The big thing for me is that I need to have the feel of the team and to make certain that as a group we don’t get too high or too low,” Callahan said. “My preparation is a little bit different in that regard.

“I try to get the feeling in the room on a daily basis of how to approach things. I’m not an especially vocal guy, but if there’s something that needs to be said, I’ll say it. I’ve been comfortable in the role, in interacting with my teammates. It hasn’t at all been a burden.”

There perhaps have been more charismatic Rangers captains, but never one who has better personified the team that he leads.

“Think of it, at his age, to be captain of an Original Six team, and in New York City; he handles it all properly, the way he represents himself and the team,” Richards said. “He’s done an unbelievable job as our leader.”